The present invention relates to an electronic device, particularly an electronic device having an electronic component such as an LSI chip incorporated therein, and further relates to a production method of such an electronic device.
A conventional multilayer wiring board is produced by, for example, using as a core board a double-sided board having low density wiring formed by the subtractive method or the like, and forming high density wiring on each side of the core board by the buildup method. On the other hand, the bare chip mounting method has been recently proposed wherein an LSI chip or the like is directly mounted onto a multilayer wiring board. In the bare chip mounting method, a semiconductor chip is mounted onto a connection pad portion of wiring formed on a multilayer wiring board in advance, by the use of connection means such as a bonding wire, bumps formed by solder, metal balls or the like, an anisotropic conductive film, a conductive adhesive, or a photocontractive resin. When a producing semiconductor device requires an LCR circuit component such as a capacitor or an inductor, it is externally mounted onto the multilayer wiring board like the semiconductor chip.
However, since the connection pad portion of the wiring formed on the multilayer wiring board is located at a position different from a mounting position of the electronic component such as the semiconductor chip, it is required that the multilayer wiring board be broadened in a plane direction. Consequently, size reduction of an electronic device is limited and tends to become further difficult as the number of electronic components to be mounted increases.
For coping therewith, a method is disclosed wherein a plurality of thin boards with semiconductor chips mounted thereon and a plurality of perforated frame boards having upper-lower side conducting vias are prepared in advance and, when producing an electronic device, each of the mounting boards and each of the frame boards are handled en bloc as one module and these modules are stacked in layers (JP-A-2002-343934, JP-A-2002-368185). In this method, even if the plurality of modules are layered, broadening in a plane direction of the electronic device is not required so that size reduction thereof is enabled.
On the other hand, use has been made of an electronic device that has a metal cap attached to an insulating region on the surface thereof by the use of an adhesive to thereby bear moisture resistance and electromagnetic interference resistance.
In the foregoing electronic device having the layered modules, however, connection means such as an anisotropic conductive film, a conductive adhesive, or a conductive paste is used for connection between each of the upper-lower side conducting vias forming the module and a corresponding one of wiring layers located under those vias, and there has been a problem that the width of selection of the connection means is narrowed in order to ensure a durability, particularly a durability excellent in temperature cycle. Further, there has also been a problem that fine-pitch connection between the layers is restricted. Moreover, in the conventional electronic device attached with the metal cap, there has also been a problem that the metal cap fixed with the adhesive falls off due to temperature cycle, or the heat conduction to the metal cap is poor due to the adhesive or an insulating member interposed between the metal cap and the electronic device so that the heat radiation effect by the metal cap is hardly achieved.